Apple is testing larger screens for both iPads and iPhones, the Wall Street Journal reports. According to company suppliers, Apple has “asked for prototype smartphone screens larger than 4 inches and has also asked for screen designs for a new tablet device measuring slightly less than 13 inches.” The iPhone 5 and fourth-generation iPad have screen sizes of 4 inches and 9.7 inches, respectively; rumors of a 12.9” iPad prototype appeared earlier this year. CEO Tim Cook has mentioned on numerous occasions that making larger screens for phones results in tradeoffs in overall product quality, but it’s possible that improved IGZO screen technology has enabled Apple to consider larger screens. Apple declined to comment.